Table 1.
Distribution of potential confounders between transtheoretical model intervention and control groups. Values are numbers (percentages) unless stated otherwise
| Intervention group | Control group | Total | |
|---|---|---|---|
| All subjects | 4125 (49.4) | 4227 (50.6) | 8352 |
| Boys/girls | 1995 (48.4)/2130 (51.6) | 2203 (52.1)/2024 (47.9) | 8352 |
| Ethnic group: | |||
| White | 3566 (86.4) | 3630 (85.9) | 7196 |
| Indian | 16 (0.4) | 61 (1.4) | 77 |
| African/Caribbean | 160 (3.9) | 156 (3.7) | 316 |
| Pakistani | 133 (3.2) | 114 (2.7) | 247 |
| Bangladeshi | 48 (1.2) | 37 (0.9) | 85 |
| Chinese | 104 (2.5) | 88 (2.1) | 192 |
| Mixed Race | 68 (1.6) | 102 (2.4) | 170 |
| Other | 13 (0.3) | 18 (0.4) | 31 |
| Unspecified ethnicity | 17 (0.4) | 21 (0.5) | 38 |
| Family’s smoking habits: | |||
| Mother smokes | 1227 (29.7) | 1214 (28.7) | 2441 |
| Father smokes | 1446 (35.1) | 1435 (33.9) | 2881 |
| Sibling smokes | 947 (23.0) | 971 (23.0) | 1918 |
| Best friend smokes | 831 (20.1) | 839 (19.8) | 1670 |
| Smoking habits of students at baseline: | |||
| Ex-smoker | 312 (7.6) | 359 (8.5) | 671 |
| Smoker | 547 (13.3) | 543 (12.8) | 1090 |
| Tried smoking | 1094 (26.5) | 982 (23.2) | 2076 |
| Never smoked | 2135 (51.8) | 2315 (54.8) | 4450 |
| Unknown | 37 (0.9) | 28 (0.7) | 65 |
| Stage of smoking at baseline: | |||
| Acquisition/precontemplation | 2478 (60.1) | 2657 (62.9) | 5135 |
| Acquisition/contemplation | 192 (4.7) | 166 (3.9) | 358 |
| Acquisition/preparation | 120 (2.9) | 80 (1.9) | 200 |
| Acquisition/recent action | 104 (2.5) | 86 (2.0) | 190 |
| Cessation/precontemplation | 156 (3.8) | 161 (3.8) | 317 |
| Cessation/contemplation | 97 (2.4) | 97 (2.3) | 194 |
| Cessation/preparation | 153 (3.7) | 149 (3.5) | 302 |
| Cessation/action | 126 (3.1) | 122 (2.9) | 248 |
| Cessation/maintenance | 90 (2.2) | 145 (3.4) | 235 |
| Unknown | 609 (14.8) | 564 (13.3) | 1173 |
| Deprivation: mean (SD) Townsend score | 1.65 (3.65) | 0.62 (4.18) | 7545* |
| Mean (SD) age at follow up | 14 years 240 days (120 days) | 14 years 230 days (118 days) | 8264† |
| Mean (SD) length of follow up | 359 days (35 days) | 347 days (39 days) | 8352 |
*
807 (9.7%) missing. †88 (1.1%) missing.